1. Field of the Invention
The present invention relates generally to methods and apparatus for creasing planar material and more particularly to a method and apparatus utilizing heated filaments to provide crease lines in planar material such as fiberglass-type sheets.
2. Description of the Relevant Art
Planar materials which are semi-rigid in construction can many times be folded along a predetermined line by providing a crease in the material along the designated fold line. Such fold lines are desirable in ceiling panels of the type described in copending provisional patent application Serial No. 60/148,834, filed Aug. 13, 1999 entitled xe2x80x9cCeiling System with Replaceable Panels,xe2x80x9d priority to which is claimed herein. The disclosure in the aforenoted application is also hereby incorporated by reference.
Ceilings of building structures have taken numerous forms. They may be left unfinished so that rafters or beams of the building structure itself are exposed or the rafter and beams may be covered as with drywall, wood strips, plaster or other similar finishes. Walls of building structures may be similarly finished.
Another popular ceiling system is commonly referred to as a drop ceiling where a plurality of support bars are suspended from the unfinished ceiling so as to form a matrix having a plurality of side-by-side openings defined between the support bars. The openings are filled with panels which are typically rigid acoustical panels, with the panels being supported along their peripheral edge by the support bars. Although such drop ceilings have met with some success, there are numerous disadvantages. One disadvantage is that there is very little variety in the aesthetics of the ceiling system since most acoustical panels have the same general appearance, with another disadvantage residing in the fact that the panels are rigid and brittle so that they are easily breakable and, further, due to their rigidity, they are difficult to insert into the opening provided therefore inasmuch as the support bars must partially protrude into the opening in order to provide a support surface for the panels. Panels overcoming the above shortcoming are described in the aforenoted provisional application and it will therein be appreciated that the panels are formed from flexible sheets of material, such as material having glass fibers embedded in resin, with some of the components of the panel being folded along predefined fold lines. It is difficult to fold such materials without first precreasing the material and accordingly an improved method and apparatus for providing creases in panels of this type would be desirable.
It is to overcome the shortcomings in prior art systems and to provide a new and improved method and apparatus for creasing planar sheets of material that the present invention has been made.
The present invention pertains to a new and improved system for cauterizing planar sheets of material to form creases therein along predetermined lines. In some planar sheets, such as sheets made of glass fibers embedded in resins, it is desirable to crease the material without damaging the glass fibers so that the material will remain resilient even after having been creased and folded along the crease line.
In accordance with the present invention, a pair of confronting and rotatable drums are mounted in slightly spaced relationship so that the planar material to be cauterized and creased can be passed therebetween. At least one of the drums includes at least one conductive filament or wire so that the wire can be heated to a temperature exceeding that which will cauterize the resin in a glass fiber panel.
In operation, the drums are rotated as the planar material is advanced therebetween and as the drums are rotated, the heated filament or filaments thereon engage the planar material at preselected locations to cauterize the material and thereby provide a crease in the material consistent with the size and configuration of the heated filament.